Question Controller interfacing

[ConsciousCode]

So I'm designing my own Wii portable as a learning exercise, and it occurred to me after I'd already spent a lot of time programming that the way GC+ handles button I/O is... odd? Like don't get me wrong, for beginners it's absolutely what you should go with because it's already completed, but why dedicate a whole uC to this interfacing when RVLoader already supports i2c? You'd just need a GPIO expander and ADC on the i2c bus and you'd get everything you need. Is there some particular reason joybus is being emulated? i2c shouldn't be too slow, it's 400 kHz which is well above HID response times... And afaik the AVE-RL only needs i2c for initial configuration so the i2c bus is otherwise free.

Asking because I figure I'm probably missing something and knowing the reasons for design decisions helps with learning.

Might have a possible answer to my own question, is it to aid in compatibility with GC games? To play them you have to hand off control to a different IOS (I think), at which point you no longer have control over how the controller interface works?

 

[Gman]

Replacing one microcontroller that does it all with atleast 2 other ICs doesnt seem like a good hardware trade-off. The other benefit is the GC controller "just works" and doesnt require experimental software hacks. If you want to try this by all means let us know how it goes.